US researchers have revealed that performing a standardized 60-second hair count may be a reliable method for the assessment of hair shedding. They arrived at this conclusion after studying hair loss in 60 healthy men who did not have any baldness.
"Currently, there is no widely accepted or standard method for assessing the number of hairs shed daily," write researchers at Baylor College of Medicine, Houston, in a research article that has been published in the Archives of Dermatology, one of the JAMA/Archives journals.
The article further states that the belief that men normally shed 100 hairs per day is based on the assumption that the average scalp contains 100,000 hairs, 10 per cent of which are in the telogen (resting) phase.
Lead researcher Dr. Carina A. Wasko says that this idea has not been scientifically validated, and that it does not even indicate whether shedding remains constant with age, or whether it is similar between men and women.
She revealed that all the participants in her study were given identical combs and instructions to wash hair with the same brand of shampoo for three consecutive mornings.
On the fourth day, the participants were asked to comb hair forward for 60 seconds over a towel or pillowcase of contrasting colour before shampooing.
For three consecutive days, the men combed their hair that way, and counted hairs shed.
The same procedure was carried out once again in eligible participants six months later.
It was found that men in the 20 to 40 years age group shed 0 to 78 hairs, with an average loss of 10.2 hairs per 60-second test.
The researchers also observed that men in the 41 to 60 years age group shed 0 to 43 hairs, with an average loss of 10.3 hairs per 60-second test.
The results were consistent on consecutive days for all participants.
"When repeated six months later in both age groups, the hair counts did not change much. The hair counts were repeated and verified by a trained investigator, with results similar to those of subject hair counts," say the researchers.
"In summary, the 60-second hair count is a simple, practical and objective tool for monitoring conditions associated with hair shedding. Low intrapatient variability demonstrates that dependable results over an extended period of time are obtainable. The similarity between investigator and subject hair counts indicates that patients can reliably count hairs," they add.
Based on their observations, the authors of the study conclude: "Studies of the 60-second hair count in normal women and in the setting of hair disease still need to be performed."